late 13c., "stay temporarily, reside for a time; visit;" also "reside permanently, dwell;" from Old French sojorner "stay or dwell for a time," from Vulgar Latin *subdiurnare "to spend the day" (source also of Italian soggiornare), from Latin sub- "under, until" (see sub-) + diurnare "to last long," from diurnus "of a day," from diurnum "day" (from PIE root *dyeu- "to shine"). Modern French séjourner formed via vowel dissimilation. Related: Sojourned; sojourning.
<a href="https://www.etymonline.com/word/sojourner">Etymology of sojourner by etymonline</a>
Harper, D. (n.d.). Etymology of sojourner. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/sojourner